Article and method for fitting a prosthetic, ischial containment socket to an above-knee amputee

ABSTRACT

An interface fitting module (10) for fitting the interface portion of an ischial containment socket for an above-knee amputee. The module (10) has a sleeve-like body portion (11) with proximal and distal ends (12 and 13), respectively. At least the proximal end (12) of the body portion (11) is open to receive the residual thigh (15) of an above-knee amputee. Means in the nature of a lap joint (25) are provided selectively to adjust the peripheral dimension of said body portion (11) so that it will circumscribe, and engage, the peripheral thigh (15) to the desired degree. The body portion (11) of the module (10) is sufficiently transparent to permit visual observation as to the conformity between the body portion (1) of the module (10) and the residual thigh (15) received therein. The body portion (11) is made from a material, such as thermoplastic polymeric material, which may be selectively modelled to effect localized conformity of the body portion (11) to the configuration of the residual thigh (15) received within the module (10).

This application is a division of application Ser. No. 226,128, filedJuly 29, 1988, now U.S. Pat. No. 4,921,502, issued on May 1, 1990.

TECHNICAL FIELD

The present invention relates generally to prosthetic socketarrangements employed to secure an artificial limb to the residual thighof an above-knee amputee. More particularly, the present inventionrelates to an article, and method, for fitting a prosthetic socketutilized to secure an artificial limb to the residual thigh of anabove-knee amputee. Specifically, the present invention relates to theconfiguration, and use, of a circumferentially adjustable and adeformably shapeable interface fitting module which can be accurately,and conveniently, fitted to a residual thigh in order to provide anexact negative mold of the residual limb from which the actual interfacefor a prosthetic socket can itself be fabricated.

BACKGROUND OF THE INVENTION

In the late 1940s the quadrilateral socket was introduced to the UnitedStates, and during the intervening years since its introduction the"quad socket" has been the standard design for fitting a prosthetic limbto the residual thigh of an above-knee amputee. During the approximately40 years in which the quad socket has been employed in the United Statesit has become clear, however, that there are certain problems,particularly as to comfort and stability, inherent to the use of thequad socket.

Although there are many variations to the quad socket, it consistentlypresents a horizontally oriented brim at the proximal posterior. Thehorizontal brim serves as the ischial seat upon which the user's ischialtuberosity is supported. In fact, that portion of the user's weightwhich would normally have been supported by the amputated limb istransferred to the quad socket through the ischial seat.

The geometry of the quad socket purposely provides a rather narrowdimension, measured from the anterior to the posterior wall of thesocket, in relation to the medial/lateral dimension. The aforesaiddimensional relationship of the quad socket was selected to assure thatthe socket applies pressure on the anterior of the residual thigh topush the ischium toward the posterior of the socket in order that theischial tuberosity will be forced to rest solidly on the ischial seatpresented by the brim at the proximal posterior of the socket. Toaccommodate the compression of the thigh which results within the quadsocket because of the purposely narrowed anterior/posterior dimension,the medial/lateral dimension of the socket is made relatively larger.

However, the enlarged medial/lateral dimension makes it virtuallyimpossible to provide sufficient lateral support for the distal end ofthe femur in the residual limb, as would be required to eliminate a limpduring that portion of the user's gait when the artificial limb is inthe weight bearing mode and the sound leg is swinging through to thenext step. In fact, many knowledgeable commentators are of the opinionthat the quad socket is ineffective in all but the mid-stance phase ofthe gait due to the excessive abduction of the femur permitted withinthe quad socket because of the aforesaid dimensional relationship.

Recognition of the deficiencies inherent to the quad socket is, ineffect, a challenge to the basic concept that the ischial tuberosityshould serve to transmit the majority of the weight expected to becarried by the residual limb to the ischial seat provided for thatpurpose on the quad socket. Such a challenge recognizes that thestructural arrangement of the quad socket has the basic inability tostabilize the femur when the gluteus medius fires; the arrangement ofthe quad socket, after all, provides no structure whereby the ischium isable to preclude abduction of the femur. It is this inability tostabilize the femur which results in the necessity for the user to leanlaterally in an attempt to stabilize the pelvis, thus presenting thereadily recognizable limp required of a person using the quad socket.

Specifically, as the gluteus medius pulls the femur into abduction, thepelvis slides medially because the ischial tuberosity is free to shiftalong the ischial seat of the quad socket; The unsupported femur haslittle choice but to abduct in a more pronounced attitude within thewide medial/lateral dimension of the quad socket. The pronouncedabduction imposes pain at the distal end of the femur as well as at theproximal medial portion thereof. To reduce the undesirable pressure, andthe resulting pain, the patient leans to position the torso over theabducted, distal end of the femur.

The aforesaid negative characteristics of the quad socket can beobviated by a much more recent innovation in prosthetic sockets whichemploys a narrower medial/lateral dimension and a wideranterior/posterior dimension, the relative dimensions being chosen suchthat the ischial tuberosity and a portion of the ramus of the ischium iscontained within the socket. The recently developed, narrowmedial/lateral socket configuration also employs a relatively highlateral wall which provides medially directed reactive forces proximaland distal to the greater trochanter. In this arrangement the abductionangle of the femur in the residual limb more closely approaches that ofthe femur in the sound extremity during all portions of the user's gait,thus greatly reducing the characteristic limp.

This recently developed socket design is not, however, designated by auniversally accepted appellation. At present such a socket design isdesignated as a "N.S.N.A. (Normal Shape Normal Alignment) socket," or a"narrow ML (Medial/Lateral) socket" or a "Cat-Cam (Contoured, AdductedTrochanteric, Controlled, Aligned Method) socket." The most recentimprovement of an ischial containment socket which has the desired,relatively narrow, medial/lateral dimension is disclosed and claimed inmy copending U.S. patent application Ser. No. 099,778, filed on Sept.22, 1987, now U.S. Pat. No. 4,872,879. Irrespective of the nameemployed, in order to provide an effective socket which incorporates thenarrow medial/lateral dimension a more precise fitting of the socket toeach patient is normally required for the narrow medial/lateral socket,as are multiple tests of the socket prior to fabrication of the finishedprosthetic limb. Nevertheless, the greater comfort and the improvedfunctionality that can be achieved by this new design has been thoughtto offset the inconvenience, and increased cost, at least to those whocan afford both the time and expense.

Except when using the prefabricated interface unit disclosed in theaforesaid U.S. Pat. No. 4,872,879, to fabricate either the historic quadsocket or the more recently developed, narrow medial/lateral socket, theprosthetist employs a negative model of the amputee's residual thigh. Toassure comfort to the user, it is necessary that the negative modelcomfortably contain the residual limb and reflect the position assumedby the residual limb when it is bearing the amputee's weight. The loadbearing disposition of the residual limb constitutes the condition whenthe residual limb and the prosthesis are subjected to the most stressand are most likely to cause discomfort to the amputee. Therefore, theprosthetist attempts to fabricate the interface portion of the socketsuch that it will provide the maximum support during the weight bearingmode.

Heretofore negative castings of the residual limb in its weight bearingdisposition have been made by casting a plaster mold of the thigh whilethe amputee is standing with his limb in a casting brim. A casting brimincorporates a number of individual pads which can be separatelyadjusted to engage the residual limb in a manner which attempts to mimica prosthetic socket and thereby provide maximum support to the residuallimb of the individual patient.

Once the several pads of the casting brim are disposed in what theprosthetist deems to be the most appropriate arrangement to mimic aprosthetic socket for the individual patient, the patient then removeshis limb from the brim. A plaster casting material is interposed betweenthe casting brim and the residual limb in such a way that it fullyencapsulates the residual limb. When the casting material has hardenedit comprises a negative model of the residual thigh in the weightbearing position, and that negative model is used in the production of apositive reproduction of the residual limb to which the interfaceportion of the prosthetic socket is fitted.

In order to assure comfort to the patient, and to accommodate thebio-mechanics occasioned by the interaction between the residual limband the prosthetic socket, the primary, technical objective of theinterface is to maintain the femur of the residual limb in an attitudecomparable to the disposition of the femur in the sound leg. This canbecome quite complicated as the prosthetist seeks to fabricate acomfortable interface, and particularly when using many of the brimcasting techniques employed in fitting quadrilateral sockets.

A brief description of one of the more successful brim castingtechniques for fitting the narrow, medial/lateral socket (whichtechnique has a satisfactorily easy learning curve for the prosthetistand provides consistently positive results for the patient) willimmediately substantiate the considerable improvement which results fromthe use of an interface fitting module embodying the concepts of thepresent invention. The typical brim casting technique requires severalaccurate measurements. First, the circumference of the residual limb ismeasured at approximately two inch (2.54 cm) increments along the lengthof the residual limb. The length of the residual limb, measured from theischial tuberosity, must be known, and three unique medial/lateralmeasurements, and a rather different anterior/posterior measurement,must be precisely taken. The medial/lateral measurements are taken, asfollows:

1. A firm medial/lateral measurement must be taken one to two inchesdistal to the ischium. This measurement is referred to as the DistalIschial Tuberosity measurement--i.e., the DIT--and is taken with largecaliper pads so as not to over compress the flesh of the residual limbin a medial/lateral direction.

2. A firm medial/lateral measurement must be taken from the medial sideof the ramus of the tuberosity to a point just superior to the greatertrochanter of the femur. This measurement is referred to as the Obliquemedial/lateral dimension--i.e., the OB--and is a bony measurement whichmay be taken firmly.

3. A firm medial/lateral measurement is also a bony measurement whichmay be taken firmly from the medial border of the ramus of the ischiumto the subtrochanteric area of the femur. If the ischial tuberosity ispalpated, the prosthetist will find that the measurement is actuallytaken from an area superior and medial to the ischial tuberosity. Thismeasurement is referred to as the ischial tuberosityMedial/Lateral--i.e., the ML.

An anterior/posterior measurement is also taken, but the manner in whichthe measurement is taken differs from the anterior/posterior measurementtaken for fitting a quadrilateral socket in that it is a "surfacetight," or silhouette, measurement taken with the medial/lateral fleshfirmly compressed. With the residual limb compressed in a medial/lateraldirection the anterior/posterior dimension is slightly elongated, and itis the elongated anterior/posterior dimension which is measured.Finally, the femoral adduction angle is measured with the patientholding the limbs as though the knees were pressed together into tightadduction with the pelvis.

The pads of the brim are then selectively positioned in a brim stand inconformity with the aforesaid measurements. In brief, the procedureentails:

1. Levelling the pad which constitutes the posterior wall of the brim.

2. Orienting the medial and lateral pads of the brim such that they aredisposed at a declining angle (on the order of 10° to 20°) from thelateral to the medial wall. This is necessary for the ischial tuberosityto be contained within the socket and for the pubic ramus to remain outof the socket.

3. Setting the adduction angle on the lateral bar of the brim intoconformity with that angle, as measured on the patient.

4. Setting the DIT as measured from the patient, plus approximately 1/4inch (0.635 mm) to accommodate the thickness of the plaster, on thelateral pad.

5. Checking to be certain that the medial and lateral walls are notparallel but are wider anteriorly in the region of the adductor longus.

6. Positioning the oblique pad so that it will firmly press against thepatient proximal to the trochanter with the posterior portion engagingthe posterior of the residual thigh at the mid medial/lateral point. Theoblique pad should parallel the wing of the ilium.

7. Positioning the anterior pad to the dimension of the patient plusapproximately 1/4 inch (0.635 mm), to accommodate the thickness of theplaster.

8. Establishing the circumferential measurement, defined by the brim padlocations, in conformity with the circumferential measurements of thepatient's residual limb--plus approximately one inch (2.54 cm) toaccommodate the thickness of the plaster.

9. Because this procedure forms a weight bearing cast, the evaluationperformed at this step is critical. That is, the procedure continues bypalpating the patient's residual limb to assure that: the ischium willbe contained within the socket; the pubic ramus lightly touches themedial wall; the lateral pad firmly contacts the patient; and, the femuris centralized within the flesh of the residual limb. During thisevaluation the patient wears a five ply stocking to simulate the plasterwraps subsequently applied to form the negative impression casting.

10. Readjusting the oblique pad snugly to rest against the patient'sside.

11. Checking to determine that the ischium is received approximately 1/2to 3/4 inch (1.270 mm to 1.905 mm) within the socket--too great a depthapplies pressure to the coccyx, blocking hip extension. A full range ofhip motion is required; adduction or extension must not be blocked.

With the components of the brim thus properly disposed, the brim isprepared by applying, and smoothing, plaster splints to the medial andposterior surfaces of the brim in order to assure accurate copying ofthe brim contour. The patient is prepared by applying approximately twolayers of an elastic plaster wrap over the thin stockinet which shieldsthe patient's residual limb, and thereafter applying approximately twoadditional layers of a rigid plaster wrap. Preparation of the residuallimb is concluded by applying a plaster splint against the proximaltrochanteric region which is held firmly in position by the oblique pad.Particular care is taken to provide cover high on the lateral side ofthe hip, at least to the level of the iliac crest.

After concluding the aforesaid pre-preparation, the patient inserts thecovered, residual limb into the brim fixture. The pubis should lightlycontact the medial wall of the brim to assure that the residual thighhas been inserted into the brim to the proper depth. The patient thenforcefully adducts the residual limb.

If the measurements have been accurately taken, and properly transferredto the brim, the brim will form the proximal socket shape while theprosthetist directs his, or her, attention to the distal aspect of theresidual limb. One hand is employed to centralize the femur within thetissue of the residual limb by pulling the distal medial tissue in alateral direction. The other hand is used to create an angulardisposition to the distal, lateral area of the residual limb in order tostabilize the femur and protect the distal end of the residual limb.When the plaster has completely hardened, the brim is lowered and thepatient removes the residual limb from the resulting negative casting.

However, even with careful attention to detail while performing the mostwidely accepted of the prior known interface fitting techniques, it isimpossible to assure that a completely satisfactory interface has beenfabricated prior to actual use of a socket which incorporates theresulting interface. Thus, it has heretofore been generally requiredthat a plurality of check sockets be made before finalizing the fitting.

Hence, while a plaster cast of the residual limb can provide a highlyaccurate and effective model for use in fabricating a quad socket, theprocess often proves time consuming and expensive. Numerous adjustmentsare often required properly to position the casting brim before thecasting can be made. Moreover, the casting process is itself quiteinvolved and requires close attention to detail. Unfortunately, if thecasting proves to be improper, the entire process must be repeated.

In addition, the disposition of the residual limb within the castingbrim may be such that the limb is unduly flattened against, or tooloosely engaging, one of the adjustable brim pads, and the prosthetistcan not always determine that situation until the model is completed, orworse, until the patient tries the resulting socket.

SUMMARY OF THE INVENTION

It is, therefore, a primary object of the present invention to providean improved article and method by which to fit the interface of aprosthetic socket for securing an artificial limb to the residual limbof an above-knee amputation, the improved article being as well adaptedto the fitting of an interface for use in conjunction with the historicquad socket as with the relatively new, highly desirable, narrow,medial/lateral socket configuration.

It is another object of the present invention to provide an interfacefitting module, as above, which eliminates the need for making a castnegative impression of the entire residual limb.

It is a further object of the present invention to provide an interfacefitting module, as above, which virtually eliminates the need for makingmultiple socket checks.

It is still another object of the present invention to provide aninterface fitting module, as above, which virtually eliminates bothlocalized pressure points and gapping, resulting in a total contactsocket.

It is yet another object of the present invention to provide aninterface fitting module, as above, which may be fabricated from amaterial that can be selectively modeled with relative ease to conformto the configuration of the residual limb.

It is a still further object of the present invention to provide aninterface fitting module, as above, which is preferably transparent inorder to enable the prosthetist visually to detect blanching and gappingfor precise modelling of the interface fitting module to the residuallimb.

It is an additional object of the present invention to provide aninterface fitting module, as above, which can be conveniently providedin several basic sizes, both right and left, for use with virtually allmale and female patients, child or adult.

These and other objects of the invention, as well as the advantagesthereof over existing and prior art forms, which will be apparent inview of the following detailed specification, are accomplished by meanshereinafter described and claimed.

In general, an interface fitting module embodying the concepts of thepresent invention has a sleeve-like body portion. At least the proximalend of the sleeve-like body portion is open to receive a residual limb.Means are provided selectively to adjust the peripheral dimension of thebody portion so that it will circumscribe, and engage, a residual limb.The body portion of the module is sufficiently transparent to permitvisual observation as to the conformity of the module to the residuallimb received therein. The material from which the body portion isfabricated is selected to permit modelling of the module as necessary toeffect localized conformity of the module to the configuration of theresidual limb received therein.

One exemplary interface fitting module, deemed sufficient to effect afull disclosure of the subject invention, is shown by way of example inthe accompanying drawings and is described in detail without attemptingto show all of the various forms and modifications in which theinvention might be embodied; the invention being measured by theappended claims and not by the details of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a generally anterior/medial perspective view which depicts aninterface fitting module embodying the concepts of the present inventionand adapted to be used in forming a socket for attaching a prostheticlimb to the right, residual thigh of an above-knee amputee;

FIG. 2 is an anterior, elevational view of the interface fitting moduledepicted in FIG. 1;

FIG. 3 is a proximal, plan view of the interface fitting module takensubstantially along the line 3--3 of FIG. 2;

FIG. 4 is an anterior, elevational view of the interface fitting moduledepicted the previous views, represented as being fitted to the right,residual thigh of an above-knee amputee; and,

FIG. 5 is an lateral, elevational view taken substantially along theline 5--5 of FIG. 4.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

One representative form of an interface fitting module embodying theconcepts of the present invention is designated generally by the numeral10 on the accompanying drawings. The representative interface fittingmodule 10 is preferably fabricated with a sleeve-like body portion 11having open proximal and distal ends 12 and 13, respectively. The bodyportion 11 of the module 10 also tapers progressively from the proximalend 12 to the distal end 13 such that the peripheral dimension of thebody portion 11 is normally greater at the proximal end 12 than it is atthe distal end 13. An amputee's residual thigh 15 (FIGS. 4 and 5) may beinsertably received through open, proximal end 12 of the module 10.

In order to accommodate the residual thigh 15 in the desired manner, thebody portion 11 of the module 10 has a posterior wall 16 which mergesinto opposed medial and lateral walls 18 and 19, respectively. Themedial wall 18, in turn, merges into an anterior wall 20. The lateralwall 19 merges into, and terminates as, an extension 22 which isdisposed generally parallel to the anterior wall 20. In fact, theextension 22 and the anterior wall 20 are disposed in overlappingrelation to form a lap joint 25.

The overlapping relation of the extension 22 and the anterior wall 20thereby also effects a peripheral discontinuity 26 which extends thefull longitudinal length of the body portion 11. That is, thediscontinuity 26 extends from the proximal end 12 through the distal end13 of the body portion 11. The discontinuity 26 permits the peripheraldimension of the body portion 11 to be adjusted by sliding thecontiguously juxtaposed, and overlapping, extension 22 and the anteriorwall 20 in whatever direction is required to vary the extent to whichthey overlap. The extent of the overlap can also be progressivelyvaried, to some degree, between the proximal and distal ends 12 and 13,respectively, in order to accommodate the particular "conicity" of theresidual thigh 15 received therein.

The body portion 11 of the module 10 is provided with a brim 28, whichforms a seat that underlies, and supports, the patient's ischialtuberosity. Specifically, the proximal end portions of the posteriorwall 16 and the medial wall 18, at least in proximity to the juncture ofthose walls, terminate in the brim 28 which extends generally outwardlyfrom the proximal ends of the adjacent posterior and medial walls 16 and18, respectively. It is important that the ischium receive propersupport, because the amputee's weight will be transferred through theischium to the interface when the patient is wearing the actualprosthesis. It is the brim 28 which provides the desired support to theischium, as well as comfort to the wearer.

The longitudinal dimension of the body portion 11 is such that thedistal end 13 of the module 10 will be located beyond the distal end 29of the residual thigh 15.

The interface fitting module 10 may be molded from a transparent,polymeric, thermoplastic material. As is hereinafter discussed inconsiderably greater detail relative to the explanation as to thefitting of the module 10 to the patient's residual thigh 15, visualexamination, and observation, of the residual thigh as it is receivedwithin the module 10 greatly facilitates determining the necessaryadjustments which are, in turn, readily imparted to the module by virtueof its thermoplastic composition. One particularly suitablethermoplastic material for fabrication of the module 10 is the ionomerfamily of resins commercially available under the brand name SURLYN.SURLYN is a registered trademark of E.I. DuPont de Nemours & Co. Ofcourse, it must be understood that the present invention is in no waylimited to the use of any particular resin.

It is envisioned that the module 10 may be initially made in threegeneral sizes, such as small, medium and large, both right and left. Tofit a particular amputee, a module 10 is selected which is approximatelythe same circumferential dimension as the amputee's residual thigh 15.The module 10 is then exactly fitted to the amputee as hereinafter morefully described.

Lotion is applied to the skin of the patient's residual thigh 15 inorder to facilitate insertion of the residual thigh 15 into the module10. Before the module 10 is donned, however, the circumferentialdimension of the residual thigh 15 is measured at a plurality oflongitudinally spaced locations along its length. Those dimensions arerecorded, and the locations where the measurements were taken are markeddirectly upon the skin of the patient's residual thigh. Verticalreference lines are also applied to at least the anterior and lateralsurfaces of the residual thigh 15.

The prosthetist transfers the circumferential measurements of theresidual thigh to the outside of the module 10, and by manipulating thelap joint 25 the circumferences of the module 10 at several locationsalong the length thereof are brought into conformity with thecircumferences of the residual thigh at corresponding longitudinallocations, even before the patient dons the module 10. Strips 30 of tapeare applied across the lap joint 25 temporarily to secure the adjustedcircumferences of the module 10.

The residual thigh 15 is then inserted through the open, proximal end 12of the module 10. When the residual thigh 15 is insertably receivedtherein it will rest against the posterior wall 16 of the module 10,with the medial, lateral and anterior walls 18, 19 and 20, respectively,embracing the corresponding surfaces on the residual thigh 15. Thedistal end 13 of the module 10 is placed on a support, such as a stool,so that the amputee can stand upright with the interface fitting module10 containing the residual thigh 15 and bearing the appropriate share ofthe amputee's weight.

The prosthetist then performs a visual examination of the residual thigh15 through the transparent body portion 11 of the module 10 to becertain that there are no rolls of flesh formed at the proximal brim 28and that there are no red or white areas of skin. If necessary, therelative disposition of the extension 22 and the anterior wall 20 may bemanipulated, by virtue of the lap joint 25, to effect a more exactingcircumferential engagement of the body portion 11 with the residualthigh 15. When the desired circumferential engagement of the module 10to the residual thigh 15 has been achieved, the disposition of the lapjoint 25 may be re-secured by the strips 30 of tape, as depicted inFIGS. 4 and 5.

All circumferential measurement marks 31, and vertical reference lines32 marked on the skin are then traced onto the exterior of the module10, and an extra wrap 33, or two, of tape may be applied to assure thatthe lap joint 25 will remain secured.

The module 10 is then removed, and perhaps three longitudinally spacedbores 34 are drilled through the overlapping extension 22 and anteriorwall 20 to receive two-piece screws, or threaded rivets, 35 by whichpermanently to secure the relative disposition of the extension 22 andthat portion of the anterior wall 20 which forms the lap joint 25.Thereafter, the strips 30, and wraps 33, of tape are removed to allowunobstructed visual observation of the residual thigh 15 through thebody portion 11 of the module 10, and the patient reinserts the residualthigh 15 into the module 10.

Once again the patient applies an appropriate portion of his, or her,weight to the module 10 and the prosthetist is able to see through thetransparent interface fitting module 10 to observe the amputee'sresidual thigh 15. The skin is palpated to identify localized areas ofthe module 10 which too tightly, or too loosely, engage the residualthigh 15. Those localized areas are marked directly on the walls of themodule 10. The module 10 is then removed from the residual thigh 15, andby use of an ordinary hot air gun, the module 10 is heated at the areaspreviously marked. When sufficiently heated and pliable, the walls ofthe module 10 may be modelled as required to correct the ill-fittingareas which the prosthetist marked. The module is repeatedly replacedonto the residual thigh 15, and marked, heated and modelled until aproper fit is obtained. The brim 28 may also be heated and modelled inorder to provide an exact, weight bearing seat for the amputee's ischialtuberosity.

Once the module 10 has been properly fitted to the residual thigh 15,the module is circumferentially marked as at 36 (FIGS. 4 and 5), toidentify the location at which the distal end 29 of the residual thighceases to contact the module 10. Thereafter, the module 10 is removedfrom the patient, and a plurality of relief bores 38 are drilledslightly proximal of the circumferential line 36 which identifies lossof contact between the residual thigh 15 and the module 10. The reliefbores 38 are blocked with tape 39, and the distal end 13 of the bodyportion 11 is closed, as by taping, not shown. An impression material40, such as an alginate mixture, is poured into the module 10 in orderto fill the module to a point just proximal to the level of the line 36which designates the location at which the distal end 29 of the residualthigh 15 would be located if it were in the module 10.

The residual thigh 15 is once again inserted into the module 10, and theamputee applies his, or her, body weight to the supported module 10 soas to force the distal end 29 of the residual thigh 15 into theimpression material 40. Air and excess impression material 40 arepermitted to escape through the relief bores 38, and the relief bores 38are reblocked by tape 39 until the impression material 40 issufficiently set so that the residual thigh 15 can be removed, leavingan impression of the distal end 29 of the residual thigh 15.

The resulting module 10, including the impression of the distal end 29of the residual thigh 15, is an exact negative model of the residualthigh 15 in the configuration it assumes when bearing the amputee'sweight. A positive casting of the residual thigh 15 made from thefinished module 10 permits the interface portion of a prosthetic socketto be fabricated to the exact configuration of the residual thigh 15 thefirst time. The interface of the resulting socket thus provides maximumsupport to the ischial tuberosity and maximum of comfort for theamputee.

As should now be apparent, the present invention not only provides animproved article and method by which to fit the interface of aprosthetic socket employed to secure an artificial limb to the residualthigh of an above-knee amputee but also accomplishes the other objectsof the present invention.

I claim:
 1. A method for fitting the interface portion of an ischialcontainment socket to the residual limb of an above-knee amputeecomprising the steps of:providing a hollow, transparent, thermoplastic,sleeve-like interface fitting module that has a peripheral discontinuitywhich extends between the proximal and the distal ends of the module;inserting a residual limb through the proximal end of the module intothe hollow interior thereof; adjusting the peripheral dimension of themodule to bring it into general conformity with the configuration of theresidual limb received therein; securing the adjusted peripheraldimension of the module; marking those localized areas on the modulewhich blanch the skin of, or gap away from, the residual limb receivedtherein; removing the residual limb from the module; heating the marked,localized areas of the module; modelling the heated areas of the moduleto bring them into the desired engagement with the residual limb; and,repeating the previous three steps, as required.
 2. A method for fittinga module, as set forth an claim 1, comprising the additional stepsof:manually manipulating the distal end of the residual limb, throughthe open distal end of the module, as required to dispose the residuallimb within the module.
 3. A method for fitting a module, as set forthan claim 2, comprising the additional steps of:closing the distal end ofthe module; inserting a molding material within the module; and, castingthe configuration of the distal end of the residual limb in situ withinthe module.
 4. A method for fitting a module, as set forth in claim 3,comprising the additional steps of:removing the residual limb from themodule after the casting of the distal end of the residual limb hashardened; employing the negative impression of the residual limb formedby the module and the casting contained therein to cast an accurate,positive impression of the residual limb from which to fabricate theinterface of an ischial containment socket.